Varnish oil and method of treating same



Patented Nov. 5, 1940 UNITED. STATES PATENT OFFICE VARNISH OIL ANDIVIETHOD OF TREATING SAME No Drawing. Application August 23, 1938,Serial No. 226,326

' 2 Claims. (01. 134-56) This invention relates to varnish oils and hasfor its principal object the improvement of their drying or film-formingqualities. More specifically, the invention relates to tung oil and the5 treatment thereof to control gelation during polymerization to insuremaximum drying qualities. This application is a continuation in part ofour application Serial No. 312112;, filed August 21, 1935.

Several processes for the treatment of tung oil have been proposed, suchas rapid heating and cooling through the critical temperature range; andthe use of gel inhibiting catalysts. These methods involve theproduction of decomposition products which influence the solubility ofthe gel in the unpolymerized constituents.

Although tung oil is normally very fast drying, when heated according tothe ordinary gelation control methods, particularly the second onementioned above, some of the drying strength seems to be lost,necessitating the use of abnormally large amounts of metallic driers.

Those familiar with the known methods of treating tung oil haverecognized the fact that viscosity increase on heating of tung oil isnot a uniform function of the degree of polymerization, althoughheretofore it has been difilcult, if not impossible, to promote usefulpolymerization withcut subjecting the oil to heavy increase in viscosityfrequently even to complete gelation.

Tung oils in which the gelled polymer is present to any appreciableextent are relatively less soluble in the ordinary varnish solvents andgenerally exhibit poor drying qualities.

We have found that by the addition of small quantities of soluble ironcompounds, preferably iron linoleate, to the oil during heating, thegelation is modified and the polymerization proceeds to the preferredfast drying non-frosting type,

from which varnishes may be made which exhibit exceptionally fast dryingand require the minimum quantities of metallic drying salts to promoteinitial set and final dry well within the time ordinarily required forthese functions.

While lead linoleate and thorium linoleate have been heretoforesuggested, we have found that the results obtained by the use of thesematerials are very different from the results obtained with ironlinoleate. We have prepared varnishes which were alike in all respectsexcept that different linoleates were used, the same being the iron,lead, cobalt, manganese and thorium linoleates. No other driers wereused.

Wood panels were then coated with thesedifferent varnishes, three coatsbeing applied to each panel and then the panels were exposed to the sameweather conditions for a period of between two and three months. Incoating the panels we allowed a drying time of forty-eight hours betweencoats, and while the iron linoleate varnish dried in eighteen hours, theothers required from three to four days to dry under ordinary conditionsand, therefore, we dried the panels in a warm place, the temperaturebeing about F. Asa result of these tests we have conclusivelyestablished that the efiect of the iron linoleate 10 on the tung oil isradically different from that of each of the other linoleates mentioned.While the iron linoleate varnish dried to a good gloss and gave a filmwhich showed good durability on the exposure test, the other varnisheshad a 15 lower gloss and in the exposure test went flat and becamechecked. It is a well known fact that the use of driers results inshortening the life of the film and that the more drier used the soonerthe film becomes brittle and breaks down, so that our 20 process oftreating the oil, because of the reduction in the amount of drierrequired, has the advantage of increasing the life of the film. Afurther advantage is that films from oil made by this process may berecoated without lifting while 25 still quite tacky.

The following examples illustrate useful formulas and successfulprocedure whereby sealing oils and waterproof varnishes may bemanufactured. In each example is shown a small 0 quantity of inhibitivecatalyst. This material is not essential to the success of the operationbut it does make the operation easier to carry out on a slow fire or bya less skilled operator. Contrary to the experiences in the use of theseanticatalysts according to earlier methods, they seem to have little ifany effect on the ultimate drying of the materials made in accordancewith the formulas given in the following examples.

Varnishes made according to the examples given require the use of onlyabout one to one 40 and one-half gallons of liquid drier per hundredgallons of varnish as compared to three to five gallons required ifordinary methods be used in the cooking of the varnish. They alsoexhibit Mineral spirits gals 50 Heat the tung oil to 350 F. Add theinhibitive catalyst. Heat to 400 F. and add the iron linoleate. Stir andheat to 500 F. Cool kettle to 480 F. Let cool for body and reduce.

EXAMPLE No. 2

Mixing varnish Ester gum lbs 100 Inhibitive catalyst oz Iron linoleatelb Tung oil gals 40 Turpentine gals Mineral spirits gals 50;

Melt the ester gum in 5 gallons of tung oil to 300 F. and use as acheck. In another kettle heat 35 gallons of tung oil to 350 F. and addthe inhibitive catalyst. Heat to 400 F. and add the iron linoleate. Heatto 580 F. and add the above check. Cool to 480 F. Let-cool for body andreduce. a

. EXAMPLE N0. 3

Spar type mixing varnish East India copal lbs 96 Iron linoleate lbInhibitive catalyst oz Tung oil gals 24 Blown fish oil gals 6 Perillaoil gals 6 Mineral spirits gals 60 Heat the tung oil to 350 F. and addthe inhibitive catalyst. Heat to 400 F. and add the iron linoleate. Stirand heat to 525 F. Pull from the fire and add the perilla oil and thefish oil. Add the gum. Heat to 580 F. with stirring. Cool kettle to 540F. Let cooland reduce.

The inhibitive catalyst in the above examples may be oil solubleselenium, antimony sulphur, or arsenic compounds. I

While in the foregoing examples we have specified definite amounts ofthe: iron compound which do not cause any apparent darkening of thevarnish, it is possible to use relatively larger amounts of the ironcompound, although this may result in some darkening of the varnish andthe invention is, therefore, not limited to the exact proportions statedin the examples. While we have specifically mentioned tung oil, we havefound that similar results may be obtained by the use of oiticica, whichis a Brazilian product of a constitution similar to tung oil and it willbe understood that where we have used the term tung oil in the claims,we intend the term to include its equivalent oiticica.

In the foregoing examples we have specifically mentioned iron linoleate.The iron compound works on the fatty acid and if linseed oil is cookedwith the tung oil and iron sulphate, chloride,

acetate or naphthenate is used in place of the linoleate, thelinseed oilwill react with any of these iron compounds and form the linoleate whichwill act on the tung oil even though linseed oil is present: If nolinseed oil is used, these iron compounds will react with the tung oilto form the tungate. Hence it is possible to obtain the desired resultsby using the various iron compounds-mentioned. 1 We have also found thatif an ir'on-gstirrer is used during the cooking; the fatty acid willreact with the iron and substantially the same results will be obtainedas when the ironlinoleate is introduced directly.

Having thus described our invention, we claim:

1. The hereindescribed method of treating tung oil to inhibit gelation,during polymerization and to give to the oil the quality of forming anonfrosting relatively fast-drying film which consists in heating theoil to about 400 F., then incorporating therein iron linoleate in theproportion, of not substantially less than one-half pound to fiftygallons of tung oil, then heating to at least 500 F.'while stirring toeffect the desired 7 RALPH F. SCHNEIDER. RALPH HOWARD COE. ELMER E.WARE.

